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By K Nilsson, D Connelly

Troy Resources acquired the Karouni Gold Project in Guyana, South America in 2014 and immediately proceeded to a Pre-Feasibility Study and project implementation. The study considered two open pit mines feeding a conventional carbon in leach (CIL) gold plant with a capacity of 1Mtpa. The study assumed a total of 2.61 million tonnes of ore with an average grade of 3.84 g/t gold with a recovered gold production of 303,526 ounces over a three year mine life.The project development involved drilling metallurgical test holes, securing second-hand major pieces of equipment where suitable, and arranging shipping to Guyana. The remote location meant logistical considerations were paramount. The plant consists of conventional two-stage crushing with single stage ball milling and a gravity circuit. The tailings circuit includes DETOX.The extremely high rainfall presented challenges with water management and the necessity to dispose of clean water to the environment. The DETOX was also mandatory due to the highly sensitive environment and past history in the area. The criticality of this meant that in the design, any cyanide in the tailings would precipitate in a plant shutdown.Lessons were learned and the project has been both profitable and successful for Troy Resources in a new operating location. In addition, the project has created jobs, delivered royalties and brought new skills into an area where previously there was little current mining activity.CITATION:Nilsson, K and Connelly, D, 2015. Karouni Gold Project from drill core to commissioning, in Proceedings MetPlant 2015, pp 197–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By S. S. Gajin

The paper deals with parametric vibrations of an axially loaded pile. The dynamic model is derived by means of Hamilton's principle and reduced to a partial differen­tial equation with variable coefficients and corresponding initial boundary conditions, taking into account the influence of the axial force. By means of Galerkin's method, the partial equation is further reduced to a Matheu-Hill's matrix partial differential equation of the second order. Since the problem of the dynamic stabili­ty has been expressed only for standing piles, the paper analyses in detail two stan­ding piles, one which is restreined, whereas the other is hinged at the toe. In both cases it is assumed that head horisontal displacement is prevented. Using Ruunge-Kutt's method, a computer analysis in the time domain is given for the characteristic parameters and possible boundary conditions. The paper analyses the stationariness of the process, as well as the dependance of the critical excitation frequency upon the pile parameters. The results have been illustrated by respective diagrams.

Jan 1, 1989

By Mitchell L. Fong

The Bay Area Rapid Transit (BART) District will be extending BART service south along an 8.7-km (5.4-mile) -long corridor in the city of Fremont, California as part of the Warm Springs Extension (WSX). The WSX project will link the existing BART system to the future BART to San Jose extension. A segment of WSX is located in Fremont Central Park (referred to as the Fremont Central Park Subway Project). The Fremont Central Park Subway is considered the most complicated and geotechnically challenging portion of the project with an underground subway box being constructed near the active Hayward Fault which is capable of ground motions up to 0.75 g and is located in an aquifer which is used for water storage and supply. Soil-structure interaction analysis was used in the design of the subway box to resist deformations due to earthquake ground motions. A water-tight excavation support system has been designed to allow subway box construction while minimizing impacts to the aquifer.

By Alexsandro Marcio da Silva

Com o objetivo de prover informações precisas, coesas e em tempo real aos gestores da Diretoria da Usina Presidente Vargas (UPV) para a tomada de decisões, foi criado o projeto para Gestão de Indicadores de Desempenho em Tempo Real com o foco no processo produtivo e performance das áreas de Laminação (a quente e a frio), Zincagem e Folhas Metálicas. O projeto foi desenvolvido em fases, onde cada fase contemplava um determinado número de equipamentos, áreas e plantas, com visualização em drill down. Utilizando os conceitos de Data Visualization e Operational Intelligence, foi possível integrar e centralizar as informações de diversas fontes de dados, tais como, PIMS, MES, LIMS, ERP, Supervisórios, PROCOM's e entradas manuais. Padronizar as informações de controle do processo produtivo entre os gestores facilita a identificação de problemas e suas causas, e permite analisar simultaneamente várias áreas e plantas. Exibir em tempo real perdas operacionais em decorrência de desvios de processo, torna o processo de tomada de decisão mais rápido e assertivo, contribuindo para a melhoria da performance dos equipamentos, redução de riscos de falhas, e além disso aumenta a vida útil dos equipamentos e otimiza a monitoração dos processos.

Jul 30, 2018

By C. E. M. Meskers

End-of-life Electronic and Electrical Equipment, o_cially called WEEE, is unjustly regarded as mainly a waste management problem. What is structurally overlooked is the enormous resource impact of these devices. EEE rep- resents a tremendous metal resource, which should be uti- lized through e_ective recycling, which has a much lower environmental footprint than primary production. The actual amount of end-of-life EEE recycled today is embar- rassingly low since insu_cient EEE is collected and part of the collected EEE is exported to developing countries, where it is largely not entering o_cial recycling systems. To achieve a global recycling society issues like technol- ogy, economics, life cycle structure, stakeholder aware- ness and legislation have to be addressed in a global, co-operative manner so that sustainable closed product cycles can be obtained. Requirements for a "global re- cycling society" are de_ned to address today's reality of global ows of used consumer products, taking into ac- count the likely needs of the future.

Jan 1, 2009

By A. T. Stroebel

Diatomite deposits, the skeletal remains of tiny aquatic plants called diatoms, are found in many parts of the world. Only a few of these de- posits are of commercial value. Open pit mining is used in nearly all deposits now being worked. Processing methods range from simple drying, crushing, sizing and packaging to carefully controlled and highly sophisticated calcining and air classification procedures, employing the latest control and testing techniques. The major uses of processed diatomite are in filtration as filter aids and fillers and extenders.

Jan 1, 1979

Using DEM to Model Industrial Banana Screens

Sep 13, 2010

By Timothy J. Orr, Robin J. Burgess-Limerick, Jennica L. Bellanca, MARGARET E. RYAN

Powered haulage continues to be a large safety concern for the mining industry, accounting for approximately 50%of the mining fatal accidents every year. Among these fatal accidents, haul-truck-related accidents are the most common, with 6 of 28 and 6 of 27 fatal accidents occurring in 2017 and 2018, respectively. To better understand why these accidents continue to occur and what can be done to prevent them, researchers reviewed the 91 haul-truck-related fatal accidents that occurred in the USA from 2005 to 2018 and performed bow-tie analyses using the final reports published by the Mine Safety and Health Administration. The analyses explore the context of the accidents with a focus on the initiating event, event outcome, hazards present, and possible preventative and mitigative controls. Overall, the vast majority of the accidents resulted in a haul truck colliding with the environment, and the majority of these events were initiated by loss of situational awareness or loss of control. The majority of the hazards were related to design and organizational controls. The results of this study suggest a need to investigate operator decision-making and organizational controls and to focus on improving design and operation controls such as mine design and operational procedures.

Feb 22, 2021

By G. M. Steed, A. O. Oyinloye

The deposit lies in amphibolite-facies biotite granite-gneisses of Proterozoic age, 4 km east of a major crustal break known as the Ifewara-Zungeru fault. Gold mineralisation is contained in a zone of quartz-carbonate (mainly calcite) veins and hydrothermally altered gneisses with associated small-scale intrusions along a steeply dipping second-order fault zone that roughly parallels the main fault. Gold is present mainly at grain boundaries between quartz and carbonate as discrete particles up to 100 micrometres in size, in general association with sparse, scattered pyrite, pyrrhotite and some base metal sulphides. Adjacent to the gold-bearing zone the granite-gneisses have been hydrothermally altered with minor volume increase, most notable enrichment being in K2O, S, Pb and Cu (and Au). High concentrations of Th, Y, Ce and Zr in the granite-gneisses imply derivation from S-type granites. It is likely that their high heat production capacity maintained the high temperatures needed to transport gold in the hydrothermal systems. It is most probable that the mineralisation dates from the Pan-African orogeny (650-450 Ma)

Apr 1, 1996

By J Hall, A Gallardo, M Strizek

Mineralogy and coproponents Sino Iron, International Minerals and Austeel are in the process of developing four world class magnetite iron ore mines with multiple open pits along a 25 km strike length of Brockman Iron Formation to the south of Cape Preston on the West Pilbara coast. The close proximity of the proposed pits raises some challenging project approvals and environmental management issues relating to the impacts of dewatering at individual projects and the cumulative impacts of progressive development on local and regional groundwater resources, which includes a large fresh water aquifer system in the Fortescue River alluvium.This paper presents an outline of the hydro-environmental impact assessment process adopted and the key result that the cumulative impacts of dewatering at all four projects on the local brackish groundwater system in the basement rocks is only marginally more than the impact of any one project on its own, and that the impact on the Fortescue River alluvium aquifer is negligible. The paper also presents an outline of the proposed integrated water management approach that will involve coordinated monitoring, ongoing impact assessment and management, and reporting programs for all projects.

Jan 1, 2009

By AIME AIME

WITH the example of the steel open-hearth men and their round table conference before the copper men, the query naturally arose "Why cannot we do likewise?" The advantage of pooling and comparing knowledge on smelting in the copper reverberatory furnace seems particularly pertinent at this time when all metallurgical economies possible must be rigorously enforced. A great deal of data had also been obtained and filed during the period of litigation over the Carson patent, and it would naturally be available with the cessation of further suits. With these ideas in mind, H. Foster Bain took up the advisability of holding such a conference directly with the heads of all the companies in the United States operating copper reverberatories, and found a nearly unanimous response. The mining companies appointed representatives directly, or indicated to the heads of various metallurgical operations what members of their staffs should be sent to such a conference.

Jan 1, 1930

By W. C. Lacy

Stratabound copper ore bodies in thick Proterozoic metamorphosed sedimentary and volcanic rocks at the Tong Kuang Yu Mine in southern Shanxi Province of China were considered as possibly being amenable to block cave mining. Initial evaluation of caving characteristics was based upon old calyx drilling records, limited underground mining experience and geological mapping, a few diamond drill holes and measurements in surface subsidence features. Classification and mapping distribution of rock quality types aided in mine design, prediction of fragment sizing and explosive requirements, cave assist and ground support requirements. Comparison is made between early feasibility predictions and actual mine experience.

Jan 1, 1989

The beach sand industry is the only Australian mineral industry which, so far, has used electrostatic separation on a full commercial scale. The main application of the process is for the separation of rutile from zircon. Laboratory work has demonstrated that electrostatic methods are effective for ilmenite-monazite and cassiterite-zircon separations, thus facilitating the production of high grade monazite and cassiterite products from top-strip table concentrates, but the commercial application of these processeshas been rather limited so far. Overseas, electrostatic methods are becoming more widely used for the treatment of granular material which is not amenable to flotation. The use of electrostatic separation for the treatment of ores other than beach sands has been investigated in this laboratory 1, 2, 3, and two pilot separators were built during i953 to carry out field tests. Of these, the first was an inclined feed plate separator for the removal of silica from granular lime-sand in Western Australia, the second a conductance roll separator for the removal of diamonds from alluvial gravel in New South Wales. In both cases the whole of the ore passed through the separator, not a gravity concentrate only as in beach sand practice. The two types of separator mentioned are shown diagramatically in Figs. 1 and 2.

Jan 1, 1954

By A. Pratt

Portland cement is primarily used to solidify backfill in underground mine workings and it represents a major cost in mining operations. CANMET-MMSL has invented an alternative binder technology that does not contain any amount of Portland cement and is made using waste materials, such as development rock and smelter slag. The technology has been successfully tested with many types of base metal and ferrous slag. Research conducted in collaboration with several mining operations in Canada has shown that the CANMET-MMSL binder has considerable potential as a replacement for Portland cement in mine backfill. An integral part of the overall mining operation, backfill is used for two main purposes: safety and environmental remediation. Depending on the mining method used, backfill provides a working surface, stabilizes stope and pillar walls, as well as the surrounding rock mass, and controls caving of stope backs. There are several benefits associated with the replacement of Portland cement in backfill, including reductions in (i) the footprint by placement of slag waste underground, (ii) the environmental effects and long term liability resulting from disposal and containment of slag waste on surface such as acid rock drainage, (iii) GHG as a result of reduced Portland cement usage (the production of 1 ton of Portland cement produces 1 ton of GHG), and (iv) the significant costs associated with reduced Portland cement usage.

May 1, 2010

By Eduardo Macedo Junior

O presente trabalho descreve o desenvolvimento de uma nova especificação para a Linha de zincagem numero 3 (LZC#3) da Companhia siderúrgica nacional (CSN), de grande demanda e aceitação, alta produtividade e foco nos requisitos do cliente que tangem qualidade superficial e características metalúrgicas (resistência mecânica) em aços para atendimento do mercado Norte-americano. Este novo produto tem como característica o ciclo de recozimento com velocidade alta para obtenção de microestrutura 100% encruada na saída do equipamento e limites de escoamento e resistência acima de 500 MPa. A combinação dessas características do produto junto com as características do processo tornou a especificação “ASTM-A653MSS80CL1” um grande desafio para garantir qualidade superficial sem comprometer as propriedades mecânicas especificadas assim como a integridade do equipamento. O baixo custo de produção associado a alta produtividade desse produto fazem da especificação “ASTM-A653M-SS80CL1” um produto de extrema importância para a estratégia adotada pela CSN, mantendo dessa maneira sua competitividade no mercado Norte-americano e garantindo capacidade máxima de produção do seu equipamento em tempos de retração do mercado interno.

Aug 17, 2017

By Ramin Motamed, Joseph A. W. Toth

Evaluation of the capacity of large-diameter drilled shafts using current load test methods present challenges when considering the magnitude of loads required to fully mobilize their capacities. Often, these full scale tests do not fully mobilize the capacity through side resistance. Therefore, the need for innovative solutions to extrapolate side resistance and interpret nominal capacity are of key interest. In this study, we evaluate three methodologies for extrapolating unit side resistance based on bi-directional load test data. Fellenius (2001) presented these methods for interpretation of pile capacity using static load tests. Our interpretations are based on the evaluation of 116 load tests. Unit side resistance was calculated and reviewed for each load test and categorized using three criteria of mobilization; (A) full, (B) partial and (C) linear. This study specifically focuses on load tests that showed fully mobilized unit side resistance behavior (Criteria A). The three methodologies were applied assuming Criteria (A) load tests were mobilized to 50% of their measured values. Subsequent comparisons of each extrapolation were then compared against the full measured values for each test and generally showed good agreement. INTRODUCTION It is widely accepted that conducting load tests such as standard top-down tests or bi-directional (i.e. O- cell) tests can help designers understand load-settlement behavior and the nominal resistance of drilled shaft foundations. These load testing methods provide the advantage of confirming design assumptions as well as improving the reliability of the foundation design. The potential cost savings from the application of these methods for mid to large size projects is self-evident. For example, in a recent project in Northern Nevada, an O-cell test on a 6.9 ft diameter, 114.8 ft length drilled shaft imposed an initial cost of $125k to the project, resulting in a 15% reduction on the total foundation cost; equivalent to $1.3 million in overall savings (Pease, 2014). However, the costs of implementing such methods on smaller projects can be prohibitively expensive (Hagerty et al, 2016). Despite the clear advantages of drilled shaft load testing, the current practice is not without limitations. Performing load tests on large-diameter drilled shafts with high capacities is a challenge considering the significant loads required to fully mobilize the capacity of such foundations. In some cases, the feasibility of these tests is impractical because the associated initial cost is not guaranteed to outweigh the final savings. As a result, large scale load tests are sometimes ruled out from the design phase of projects. Furthermore, in the majority of load tests the magnitude of loads applied are specifically selected to not approach failure, so the shafts can be used in the future foundation system (i.e. production shafts). This practice of field testing restricts our knowledge of the true capacity of the drilled shaft at failure; hence the nominal resistance remains unknown.

Jan 1, 2018

By Fritz J. Klingler

From site demolition, to design, to construction, Detroit's new Tiger Stadium project is required to be completed within a short 2 ½ years from award of the design-build contract. Such extreme schedule requirements together with somewhat difficult ground conditions at the site, resulted in several challenges in the design and construction of the deep foundation system for the stadium. During the geotechnical investigation, an intermittent water bearing sand layer was encountered overlying the hardpan at the site. As a result, some concern developed regarding the potential for collapse of caisson bells within this layer, as well as the potential for flooding of the caissons during drilling. Although sand and/or ground water was encountered within about half of the caissons, standard drilling and belling methods were used, and adverse conditions were controlled in almost all cases through expeditious drilling, inspection and concreting of the caissons. This paper will present a summary of the ground conditions, design and specification requirements, and construction methods used to successfully install the caissons for this project.

Jan 1, 1999

By Frederick W. Slack

This paper will discuss the inherent value engineering associated with the design and construction of approximately 184,000 SF of anchored tieback wall, installed as part of the widening and drainage improvements for KY9 in Campbell County, Kentucky. The total project is 2.2 miles in length. The anchored walls, excavation grading and drainage total to a complete project cost of $28.4 million. This is one of the largest design-build projects undertaken by the Commonwealth of Kentucky. It also features another first for the Transportation Cabinet - the general contractor is responsible for quality control/quality assurance. The project is located just south of Cincinnati, OH and is situated along the east bank of the Licking River. The slopes along this stretch of the river have had a long history of movement and instability. The Kentucky Transportation Cabinet advertised the anchored wall portion of this project to be designed and constructed by pre-approved specialty contractors. The Transportation Cabinet provided the basic design parameters to each specialty contractor. Aspects to be discussed include the site and project history, previous attempts at slope stabilization along existing KY9, the technical proposal and bidding process, and the actual design and construction.

Jan 1, 2003

By Marcia Harris, Richard Mainiero, Michael Sapko

Since 1988, there have been 17 documented incidents in the United States and Canada in which carbon monoxide (CO) is suspected to have migrated through ground strata into occupied enclosed spaces as a result of proximate trench blasting or surface mine blasting. These incidents resulted in 39 suspected or medically verified carbon monoxide poisonings and one fatality. To better understand the factors contributing to this hazard, the National Institute for Occupational Safety and Health (NIOSH) carried out studies in a 12-foot diameter sphere to identify key factors that may enhance the levels of CO associated with the detonation of several commercial trenching explosives. The gaseous detonation products from emulsions, a watergel, and ANFO blasting agents as well as gelatin dynamite, TNT, and Pentolite boosters were measured in an argon atmosphere and compared with those for the same explosives detonated in air. Test variables included explosive formulation, wrapper, aluminum addition, oxygen balance, and density. Major contributing factors to CO production, under these laboratory test conditions, are presented. The main finding is the high CO production associated with the lack of afterburning in an oxygen poor atmosphere. Fumes measurements are compared with the manufacturer’s reported IME fume class and with the Federal Relative Toxicity Standard 30 CFR Part 15 in order to gain an understanding of the relative toxicity of some explosives used in trench blasting.

Jan 1, 2003

By Wayne N. Marchant

Introduction The issue of coal mining safety plays an important role in the United States' growing dependence on coal to supply its future needs. This article will address the federal government's role, principally the US Bureau of Mines, in meeting this challenging growth and demand while reducing the social and economic costs attributed to injuries and fatalities in underground mining. Some interesting facts and projections with respect to the nation's energy picture will be discussed. This includes the distribution of its reserves and the projected role of coal in the energy and economics of the nation's future. Underground mining will continue to be an important means of providing this coal. The author will discuss how the Bureau of Mines' research program addresses the problems of health and safety that grow out of the demand for more coal. Future projections First, a synopsis of salient facts and projections concerning the US's situation with respect to energy and the economy. Figure 1 depicts the relative quantities of recoverable energy reserves in the United States by their type. Most people are aware of the nation's use of oil. We hear a lot about natural gas. And we are aware of the controversy over the use of nuclear energy. But, while looking at Fig. 1, the question becomes, "Where will our fuel to meet the demand for energy in the future most certainly have to come from?" With 82% of the nation's recoverable fuel reserves being coal, the answer is irrefutable. Coal will be that source. Figure 2 is the present market for coal. It shows that 77% of the coal mined goes to supply electric utilities. Therefore, the coal industry as a whole is most sensitive to the trends and demands for electricity. It is less affected by what happens in other markets, such as export and direct industrial use. In fact, the coal industry is three times more sensitive to the electric utility market than to all other markets combined. Therefore, the trend in the demand for electricity must be examined. Electricity demand is expected to increase steadily over the next 15 years. It is projected to grow from its present 2.3 trillion kWh per year to 3.5 trillion kWh per year by the year 2000. The fuel to supply this increase in demand must come from somewhere. The question is "How much of this extra fuel will be coal?" Although the demand for electricity is predicted to increase, the demand for coal does not necessarily follow. Coal must maintain its fraction of the energy sources used for electricity generation if its demand is to increase at the same or greater rate as electricity. Except for a near-term dip in demand due to a slight increase in nuclear capacity, the domestic electric generation accruing to coal will go from 56% in 1985 to more than 60% in 2005. Thus, the predicted trend is for coal to become a larger part of the fuel mix for electric power generation. Similarly, looking at the most recent forecast for total coal consumption trends, it can be seen that for electric power generation alone, the coal industry must be able to supply an additional 316 Mt/a (348.5 million stpy) by the year 2000 (Fig. 3). It must be stressed here, though, that without significant improvements in mining safety, it can also be easily predicted that injuries and fatalities will increase in proportion to the increase in coal production. Will society consider that acceptable? This author does not believe so. Figure 4 examines the effect of coal prices on the price of electricity. The projections show that the already high proportion of fuel cost will become a greater fraction of the consumer price for electricity. Specifically in 1985, 36% of the price of electricity was the cost of the fuel. In 1995, 46% of the price of electricity will be the fuel cost. That implies that the price of coal will have an increasing influence on the consumer price for electricity. Thus, as coal is used more to generate electricity and as fuel becomes a greater

Jan 4, 1987